Search

Objectives: This study determined associations between respiratory viruses and subsequent illness course in primary care adult patients presenting with acute cough and/or suspected lower respiratory tract infection. Methods: A prospective European primary care study recruited adults with symptoms of lower respiratory tract infection between November 2007 and April 2010. Real-time in-house polymerase chain reaction (PCR) was performed to test for six common respiratory viruses. In this secondary analysis, symptom severity (scored 1 = no problem, 2 = mild, 3 = moderate, 4 = severe) and symptom duration were compared between groups with different viral aetiologies using regression and Cox proportional hazard models, respectively. Additionally, associations between baseline viral load (cycle threshold (Ct) value) and illness course were assessed. Results: The PCR tested positive for a common respiratory virus in 1354 of the 2957 (45.8%) included patients. The overall mean symptom score at presentation was 2.09 (95% confidence interval (CI) 2.07-2.11) and the median duration until resolution of moderately bad or severe symptoms was 8.70 days (interquartile range 4.50-11.00). Patients with influenza virus, human metapneumovirus (hMPV), respiratory syncytial virus (RSV), coronavirus (CoV) or rhinovirus had a significantly higher symptom score than patients with no virus isolated (0.07-0.25 points or 2.3-8.3% higher symptom score). Time to symptom resolution was longer in RSV infections (adjusted hazard ratio (AHR) 0.80, 95% CI 0.65-0.96) and hMPV infections (AHR 0.77, 95% CI 0.62-0.94) than in infections with no virus isolated. Overall, baseline viral load was associated with symptom severity (difference 0.11, 95% CI 0.06-0.16 per 10 cycles decrease in Ct value), but not with symptom duration. Conclusions: In healthy, working adults from the general community presenting at the general practitioner with acute cough and/or suspected lower respiratory tract infection other than influenza impose an illness burden comparable to influenza. Hence, the public health focus for viral respiratory tract infections should be broadened. (C) 2020 Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases.

Summary Background Staphylococcus aureus remains a common cause of ventilator-associated pneumonia, with little change in incidence over the past 15 years. We aimed to evaluate the efficacy of suvratoxumab, a monoclonal antibody targeting the α toxin, in reducing the incidence of S aureus pneumonia in patients in the intensive care unit (ICU) who are on mechanical ventilation. Methods We did a multicentre, randomised, double-blind, placebo-controlled, parallel-group, phase 2 pilot trial at 31 hospitals in Belgium, the Czech Republic, France, Germany, Greece, Hungary, Portugal, Spain, and Switzerland. Eligible patients were in the ICU, aged ≥18 years, were intubated and on mechanical ventilation, were positive for S aureus colonisation of the lower respiratory tract, as assessed by quantitative PCR (qPCR) analysis of endotracheal aspirate, and had not been diagnosed with new-onset pneumonia. Patients were excluded if they had confirmed or suspected acute ongoing staphylococcal disease; had received antibiotics for S aureus infection for more than 48 h within 72 h of randomisation; had a Clinical Pulmonary Infection Score of 6 or higher; had an acute physiology and chronic health evaluation II score of 25 or higher with a Glasgow coma scale (GCS) score of more than 5, or an acute physiology and chronic health evaluation II score of at least 30 with a GCS score of 5 or less; had a Sequential Organ Failure Assessment score of 9 or higher; or had active pulmonary disease that would impair the ability to diagnose pneumonia. Colonised patients were randomly assigned (1:1:1), by use of an interactive voice or web response system, to receive either a single intravenous infusion of suvratoxumab 2000 mg, suvratoxumab 5000 mg, or placebo. Randomisation was done in blocks of size four, stratified by country and by whether patients had received systemic antibiotics for S aureus infection. Patients, investigators, and study staff involved in the treatment or clinical evaluation of patients were masked to patient assignment. The primary efficacy endpoint was the incidence of S aureus pneumonia at 30 days, as determined by a masked independent endpoint adjudication committee, in all patients who received their assigned treatment (modified intention-to-treat [ITT] population). Primary safety endpoints were the incidence of treatment-emergent adverse events at 30 days, 90 days, and 190 days after treatment, and the incidence of treatment-emergent serious adverse events, adverse events of special interest, and new-onset chronic disease at 190 days after treatment. All primary safety endpoints were assessed in the modified ITT population. This trial is registered with ClinicalTrials.gov ( NCT02296320 ) and the EudraCT database (2014-001097-34). Findings Between Oct 10, 2014, and April 1, 2018, 767 patients were screened, of whom 213 patients with confirmed S aureus colonisation of the lower respiratory tract were randomly assigned to the suvratoxumab 2000 mg group (n=15), the suvratoxumab 5000 mg group (n=96), or the placebo group (n=102). Two patients in the placebo group did not receive treatment after randomisation because their clinical conditions changed and they no longer met the eligibility criteria for dosing. As adjudicated by the data monitoring committee at an interim analysis, the suvratoxumab 2000 mg group was discontinued on the basis of predefined pharmacokinetic criteria. At 30 days after treatment, 17 (18%) of 96 patients in the suvratoxumab 5000 mg group and 26 (26%) of 100 patients in the placebo group had developed S aureus pneumonia (relative risk reduction 31·9% [90% CI −7·5 to 56·8], p=0·17). The incidence of treatment-emergent adverse events at 30 days were similar between the suvratoxumab 5000 mg group (87 [91%]) and the placebo group (90 [90%]). The incidence of treatment-emergent serious adverse events at 30 days were also similar between the suvratoxumab 5000 mg group (36 [38%]) and the placebo group (32 [32%]). No significant difference in the incidence of treatment-emergent adverse events between the two groups at 90 days (89 [93%] in the suvratoxumab 5000 mg group vs 92 [92%] in the placebo group) and at 190 days (93 [94%] vs 93 [93%]) was observed. 40 (40%) patients in the placebo group and 50 (52%) in the suvratoxumab 5000 mg group had a serious adverse event at 190 days. In the suvratoxumab 5000 mg group, one (1%) patient reported at least one treatment-emergent serious adverse event related to treatment, two (2%) patients reported an adverse event of special interest, and two (2%) reported a new-onset chronic disease. Interpretation In patients in the ICU receiving mechanical ventilation with qPCR-confirmed S aureus colonisation of the lower respiratory tract, the incidence of S aureus pneumonia at 30 days was not significantly lower following treatment with 5000 mg suvratoxumab than with placebo. Despite these negative results, monoclonal antibodies still represent one promising therapeutic option to reduce antibiotic consumption that require further exploration and studies. Funding AstraZeneca, with support from the Innovative Medicines Initiative Joint Undertaking.

BackgroundDifferences in clinical impact between rhinovirus (RVs) species and types in adults are not well established. The objective of this study was to determine the epidemiology and clinical impact of the different RV species.MethodsWe conducted a prospective study of RVs infections in adults with acute cough/lower respiratory tract infection (LRTI) and asymptomatic controls. Subjects were recruited from 16 primary care networks located in 11 European countries between 2007 and 2010. RV detection and genotyping was performed by means of real time and conventional reverse-transcriptase polymerase chain reaction assays, followed by sequence analysis. Clinical data were obtained from medical records and patient symptom diaries.ResultsRVs were detected in 566 (19%) of 3016 symptomatic adults, 102 (4%) of their 2539 follow-up samples and 67 (4%) of 1677 asymptomatic controls. Genotyping was successful for 538 (95%) symptomatic subjects, 86 (84%) follow-up infections and 62 (93%) controls. RV-A was the prevailing species, associated with an increased risk of LRTI as compared with RV-B (relative risk (RR), 4.5; 95% CI 2.5 to 7.9; pInterpretationIn adults, RV-A is significantly more often detected in cases with acute cough/LRTI than RV-C, while RV-B infection is often found in asymptomatic patients.

Unfortunately, the online published article has errors in Table 1. The reference citations were not properly updated in the table.(Table presented).

Background We found amino acid substitutions in the Gglycoprotein of respiratory syncytial virus (RSV) A during the 2016/2017 epidemic in The Netherlands. Objectives We evaluated whether these alterations led to increased RSV incidence and disease burden. Study design We sequenced the gene encoding the G-protein of prospectively collected clinical specimens from secondary care adult patients testing positive for RSV during the 2016/2017 and 2017/2018 epidemic RSV season. We evaluated associations between genetic, clinical and epidemiological data. Results We included 49 RSV strains. In 2016/2017 28 strains were included, 20 community acquired RSV-A, 5 hospital acquired RSV-A and 3 community acquired RSV-B. In 2017/2018 21 strains were included, 8 community acquired RSV-A and 13 community acquired RSV-B. G-proteins of 10 out of the 20 community acquired 2016/2017 RSV-A strains shared a set of eight novel amino acid substitutions of which seven in mucin-like regions 1 and 2 and one in the heparin binding domain. This genetic variant was no longer detected among 2017/2018 RSV-A strains. Among patients carrying the novel RSV-A strain-type, 30% died. Conclusions A set of eight amino acid substitutions was found in 50% of the 2016/2017 community acquired RSV-A G-proteins. This combination of substitutions was globally never observed before. The appearance of this new strain-type coincided with an increased RSV peak in The Netherlands and was associated with higher disease severity. The transient character of this epidemic strain-type suggests rapid clearance of this lineage in our study community.

Organoids are self-organizing 3D structures grown from stem cells that recapitulate essential aspects of organ structure and function. Here, we describe a method to establish long-term-expanding human airway organoids from broncho-alveolar resections or lavage material. The pseudostratified airway organoids consist of basal cells, functional multi-ciliated cells, mucus-producing secretory cells, and CC10-secreting club cells. Airway organoids derived from cystic fibrosis (CF) patients allow assessment of CFTR function in an organoid swelling assay. Organoids established from lung cancer resections and metastasis biopsies retain tumor histopathology as well as cancer gene mutations and are amenable to drug screening. Respiratory syncytial virus (RSV) infection recapitulates central disease features, dramatically increases organoid cell motility via the non-structural viral NS2 protein, and preferentially recruits neutrophils upon co-culturing. We conclude that human airway organoids represent versatile models for the in vitro study of hereditary, malignant, and infectious pulmonary disease.

Respiratory syncytial virus (RSV) infection is a leading cause of hospitalization and mortality in young children. Protective therapy options are limited. Currently, palivizumab, a monoclonal IgG1 antibody, is the only licensed drug for RSV prophylaxis, although other IgG antibody candidates are being evaluated. However, at the respiratory mucosa, IgA antibodies are most abundant and act as the first line of defense against invading pathogens. Therefore, it would be logical to explore the potential of recombinant human IgA antibodies to protect against viral respiratory infection, but very little research on the topic has been published. Moreover, it is unknown whether human antibodies of the IgA isotype are better suited than those of the IgG isotype as antiviral drugs to combat respiratory infections. To address this, we generated various human IgA antibody formats of palivizumab and motavizumab, two well-characterized human IgG1 anti-RSV antibodies. We evaluated their efficacy to prevent RSV infection in vitro and in vivo and found similar, but somewhat decreased efficacy for different IgA subclasses and formats. Thus, reformatting palivizumab or motavizumab into IgA reduces the antiviral potency of either antibody. Moreover, our results indicate that the efficacy of intranasal IgA prophylaxis against RSV infection in human FcαRI transgenic mice is independent of Fc receptor expression.

Objectives: To describe the role of bacteria (including bacterial resistance), viruses (including those recently described) and mixed bacterial-viral infections in adults presenting to primary care with lower respiratory tract infection (LRTI). Methods: In all, 3104 adults with LRTI were enrolled, of whom 141 (4.5%) had community-acquired pneumonia (CAP), and 2985 matched controls in a prospective study in 16 primary care networks in Europe, and followed patients up at 28-35 days. We detected Streptococcus pneumoniae and Haemophilus influenzae and assessed susceptibility, atypical bacteria and viruses. Results: A potential pathogen was detected in 1844 (59%) (in 350 (11%) bacterial pathogens only, in 1190 (38%) viral pathogens only, and in 304 (10%) both bacterial and viral pathogens). The most common bacterial pathogens isolated were S. pneumoniae (5.5% overall, 9.2% in CAP patients) and H. influenzae (5.4% overall, 14.2% in CAP patients). Less than 1% of S. pneumoniae were highly resistant to penicillin and 12.6% of H. influenzae were beta-lactamase positive. The most common viral pathogens detected were human rhinovirus (20.1%), influenza viruses (9.9%), and human coronavirus (7.4%). Influenza virus, human parainfluenza viruses and human respiratory syncytial virus as well as human rhinovirus, human coronavirus and human metapneumovirus were detected significantly more frequently in LRTI patients than in controls. Conclusions: A bacterial pathogen is identified in approximately one in five adult patients with LRTI in primary care, and a viral pathogen in just under half, with mixed infections in one in ten. Penicillin-resistant pneumococci and beta-lactamase producing H. influenzae are uncommon. These new findings support a restrictive approach to antibiotic prescribing for LRTI and the use of first-line, narrow-spectrum agents in primary care. (C) 2018 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Organoids are self-organizing 3D structures grown from stem cells that recapitulate essential aspects of organ structure and function. Here we describe a method to establish long-term-expanding human airway organoids from broncho-alveolar biopsies or lavage material. The pseudostratified airway organoid epithelium consists of basal cells, functional multi-ciliated cells, mucus-producing goblet cells, and CC10-secreting club cells. Airway organoids derived from cystic fibrosis (CF) patients allow assessment of CFTR function in an organoid swelling assay. Organoid culture conditions also allow gene editing as well as the derivation of various types of lung cancer organoids. Respiratory syncytial virus (RSV) infection recapitulated central disease features and dramatically increases organoid cell motility, found to be driven by the non-structural viral NS2 protein. We conclude that human airway organoids represent versatile models for the in vitro study of hereditary, malignant, and infectious pulmonary disease.

Severe influenza virus infection can lead to life-threatening pathology through immune-mediated tissue damage. In various experimental models, this damage is dependent on T cells. There is conflicting evidence regarding the role of neutrophils in influenza-mediated pathology. Neutrophils are often regarded as cells causing tissue damage, but, in recent years, it has become clear that a subset of human neutrophils is capable of suppressing T cells, which is dependent on macrophage-1 antigen (CD11b/CD18). Therefore, we tested the hypothesis that immune suppression by neutrophils can reduce T cell-mediated pathology after influenza infection. Wild-type (WT) and CD11b-/- mice were infected with A/HK/2/68 (H3N2) influenza virus. Disease severity was monitored by weight loss, leukocyte infiltration, and immunohistochemistry. We demonstrated that CD11b-/- mice suffered increased weight loss compared with WT animals upon infection with influenza virus. This was accompanied by increased pulmonary leukocyte infiltration and lung damage. The exaggerated pathology in CD11b-/- mice was dependent on T cells, as it was reduced by T cell depletion. In addition, pathology in CD11b-/- mice was accompanied by higher numbers of T cells in the lungs early during infection compared with WT mice. Importantly, these differences in pathology were not associated with an increased viral load, suggesting that pathology was immune-mediated rather than caused by virus-induced damage. In contrast to adoptive transfer of CD11b-/- neutrophils, a single adoptive transfer of WT neutrophils partly restored protection against influenza-induced pathology, demonstrating the importance of neutrophil CD11b/CD18. Our data show that neutrophil CD11b/CD18 limits pathology in influenza-induced, T cell-mediated disease.

Progressive multifocal leukoencephalopathy (PML) is a rare and potentially fatal condition caused by a brain infection with JC polyomavirus (JCV). PML develops almost exclusively in immunocompromised patients and has recently been associated with use of fumaric acid esters (FAEs), or fumarates. We reviewed the literature and the Dutch and European pharmacovigilance databases in order to identify all available FAE-associated PML cases and distinguish possible common features among these patients. A total of 19 PML cases associated with FAE use were identified. Five cases were associated with FAE use for multiple sclerosis and 14 for psoriasis. Ten patients were male and nine were female. The median age at PML diagnosis was 59 years. The median duration of FAE therapy to PML symptom onset or appearance of first PML lesion on brain imaging was 31 months (range 6–110). In all cases a certain degree of lymphocytopenia was reported. The median duration of lymphocytopenia to PML symptom onset was 23 months (range 6–72). The median lymphocyte count at PML diagnosis was 414 cells/µL. CD4 and CD8 counts were reported in ten cases, with median cell count of 137 and 39 cells/µL, respectively. Three patients died (16% mortality). The association between occurrence of PML in patients with low CD4 and CD8 counts is reminiscent of PML cases in the HIV population and suggests that loss of T cells is the most important risk factor.

Background Staphylococcus aureus (SA) pneumonia imposes significant morbidity and mortality in mechanically ventilated, intensive care unit (MV ICU) patients despite best clinical care. We assessed efficacy, PK, AT-neutralizing antibodies (AT NAbs), and safety of suvratoxumab (suvra) in MV ICU subjects in the placebo-controlled, randomized Phase 2 SAATELLITE study (NCT02296320; EudraCT 2014-001097-34). Methods Subjects with PCR-confirmed SA colonization of the lower respiratory tract were randomized to either a single intravenous infusion of 5,000 mg suvra (n = 96) or placebo (n = 100) and followed for 190 days post dose. Efficacy endpoints were Endpoint Adjudication Committee-determined relative risk reduction (RRR) of SA pneumonia incidence in suvra vs. placebo recipients within 30 days post dose (primary endpoint, tested at 2-sided α = 0.1), incidence of all-cause pneumonia, and all-cause pneumonia or death. Serum suvra PK and levels of AT NAbs were measured through 90 days post dose and analyzed for statistical correlation. Treatment-emergent adverse events (TEAEs) and serious AEs (SAEs) were assessed through 190 days post dose. Results Baseline characteristics were similar between groups. Suvra provided 31.9% RRR in incidence of SA pneumonia vs. placebo (17.7% vs. 26%; P = 0.166), 30% RRR (P = 0.146) in incidence of all-cause pneumonia, and 23% RRR (P = 0.164) in incidence of all-cause pneumonia or death. Suvra reduced mean hospital stay and ICU duration by 3.0 and 2.4 days, resp. vs. placebo. Mean serum ± SD suvra level was 296 ± 131 µg/mL at 30 days post dose. Serum AT Nab ± SD levels reached 156.03 ± 72.48 IU/mL at 2 days post dose, declining slowly to 33.74 ± 16.04 IU/mL by 90 days post dose. AT NAbs correlated with PK (r2 = 0.7), thereby confirming functional activity of suvra over time. Proportion of subjects with TEAEs or SAEs was similar between groups: ≥1 TEAE (93.8% suvra; 93.0% placebo); ≥1 serious; and/or ≥grade 3 severity SAE (66.7% suvra; 58.0% placebo). Conclusion A single intravenous dose of suvra produced a trend toward reduced incidence of SA pneumonia, health resource savings, sustained functional exposure in serum, and an acceptable safety profile. These results support continued development of suvra in MV ICU patients. Disclosures All Authors: No reported Disclosures.

Infants are protected from a severe respiratory syncytial virus (RSV) infection in the first months of life by maternal antibodies or by prophylactically administered neutralizing antibodies. Efforts are under way to produce RSV-specific antibodies with increased neutralizing capacity compared to the currently licensed palivizumab. While clearly beneficial during primary infections, preexisting antibodies might affect the onset of adaptive immune responses and the ability to resist subsequent RSV infections. Therefore, we addressed the question of how virus neutralizing antibodies influence the priming of subsequent adaptive immune responses. To test a possible role of the neonatal Fc receptor (FcRn) in this process, we compared the responses in C57BL/6 wild-type (WT) and FcRn −/− mice. We observed substantial virus-specific T-cell priming and B-cell responses in mice primed with RSV IgG immune complexes resulting in predominantly Th1-type CD4 + T-cell and IgG2c antibody responses upon live-virus challenge. RSV-specific CD8 + T cells were primed as well. Activation of these adaptive immune responses was independent of FcRn. Thus, neutralizing antibodies that localize to the airways and prevent infection-related routes of antigen processing can still facilitate antigen presentation of neutralized virus particles and initiate adaptive immune responses against RSV.

Breast feeding reduces the risk of developing severe respiratory syncytial virus (RSV) infections in infants. In addition to maternal antibodies, other immune-modulating factors in human milk contribute to this protection. Specific dietary prebiotic oligosaccharides, similar to oligosaccharides present in human milk, were evaluated in a C57BL/6 mouse RSV infection model. During primary RSV infection, increased numbers of RSV-specific CD4 + T cells producing gamma interferon (IFN-γ) were found in the lungs at days 8 to 10 postinfection in mice receiving diet containing short-chain galactooligosacharides, long-chain fructooligosaccharides, and pectin-derived acidic oligosaccharides (termed scGOS/lcFOS/pAOS). In a Th2-skewed formalin-inactivated (FI)-RSV vaccination model, the prebiotic diet reduced RSV-specific Th2 cytokine (interleukin-4 [IL-4], IL-5, and IL-13)-producing CD4 + T cells in the lung and the magnitude of airway eosinophilia at day 4 and 6 after infection. This was accompanied by a decreased influx of inflammatory dendritic cells (CD11b + /CD11c + ) and increased numbers of IFN-γ-producing CD4 + and CD8 + T cells at day 8 after viral challenge. These findings suggest that specific dietary oligosaccharides can influence trafficking and/or effector functions of innate immune, CD4 + , and CD8 + T cell subsets in the lungs of RSV-infected mice. In our models, scGOS/lcFOS/pAOS had no effect on weight but increased viral clearance in FI-RSV-vaccinated mice 8 days after infection. The increased systemic Th1 responses potentiated by scGOS/lcFOS/pAOS might contribute to an accelerated Th1/Th2 shift of the neonatal immune system, which might favor protective immunity against viral infections with a high attack rate in early infancy, such as RSV.

Quantitative real-time PCR for the detection of respiratory syncytial virus (RSV) RNA is increasingly used to study the causal role of RSV in lower airway disease. The objective of our study was to evaluate variations in RSV RNA loads at different steps in the RNA quantification process: (i) variation in RSV RNA load within one sample (step 1), (ii) variation in the load in samples from patients who were sampled twice on the same day (step 2), and (iii) variation in the load between simultaneously taken nasopharyngeal aspirate (NPA) samples and tracheal aspirate (TA) samples (step 3). Thirty-two infants with RSV infection at the pediatric intensive care unit (PICU) were included. NPA and TA samples were taken three times a week during ventilation and were not diluted. Intrasample variation (step 1) was shown to be minimal (10 particles/ml). Intraday variation (step 2) was the lowest for samples with high viral loads (95% limits of agreement, −1.3 to +0.9 log 10 ), whereas it increased for samples with relatively lower viral loads (viral load, 10 particles/ml; n = 138 sample pairs from 20 patients). RSV loads in NPA and TA samples (step 3) were found to be the most comparable during the early phase of infection (95% limits of agreement, −1.5 to +1.4 log 10 ). The variation increased during the late phase of infection (i.e., in follow-up samples), with the loads in NPA samples remaining significantly higher than the loads in TA samples ( n = 138 sample pairs from 31 patients). In conclusion, quantitative detection of RSV RNA in undiluted mucus is a reliable method to quantify viral loads. Nasopharyngeal aspirate samples collected in the initial phase of infection can be used to predict RSV RNA loads in the lower airways.

Respiratory syncytial virus (RSV) is a major cause of respiratory tract infections in infants, with remarkable variability in disease severity. Factors determining severity of disease in previously healthy infants are still unclear. It was hypothesized that disease severity is correlated with viral load in primary RSV infection. Infants of a healthy birth cohort were included at signs of their first respiratory tract infection. Nasopharyngeal aspirate was obtained within 48–96 hr and disease severity was assessed with a previously published severity scoring model. PCR was applied to test the aspirates in a semi‐quantitative way for the presence of 10 respiratory pathogens. In case of multiple infection, the pathogen with the highest load was defined as the primary pathogen. The correlation between disease severity and viral load was analyzed. A total of 82 infants were included over a period of 2 years. Median age at first respiratory tract infection was 3 months. Pathogens were detected in 77 (94%) infants; more than one pathogen was detected in 35 (43%) infants. RSV was present in aspirates of 30 infants; in 16 aspirates RSV was the primary pathogen. A negative correlation between RSV CT‐value and disease severity was found in all RSV cases (ρ = −0.52, P = 0.003) and in cases with RSV as the primary pathogen (ρ = −0.54, P = 0.03). In conclusion, this is the first report on viral loads in previously healthy infants with RSV infection in the community. Disease severity correlated positively with viral load during primary RSV infection. J. Med. Virol. 82: 1266–1271, 2010. © 2010 Wiley‐Liss, Inc.

Objective: To investigate whether Escherichia coli bacteriuria is associated with the development of hypertension during a long-term follow-up.Methods: A prospective cohort study was performed among the participants of two population-based studies. Between 1974 and 1986 all women aged 39 to 68 years old, who lived in Utrecht, the Netherlands, were invited to participate in a breast cancer screening program. The participants completed a questionnaire, underwent a medical examination, and collected a morning urine sample that remained stored. From 1993 to 1997 another population-based study was performed. We performed a full cohort analysis for 444 women who participated in both studies. E. coli bacteriuria was diagnosed by a real-time PCR. Hypertension was defined as the use of antihypertensive medication and/or a measured systolic blood pressure of at least 160 mmHg or a diastolic blood pressure of 95 mmHg or higher. The mean follow-up was 11.5 +/- 1.7 years.Results: Forty women (9%) had E. coli bacteriuria at baseline. Women who had bacteriuria at baseline had a mean blood pressure at study endpoint of 133 +/- 20 mmHg systolic and 78 +/- 11 mmHg diastolic, and women without bacteriuria had values of 129 +/- 20 and 78 +/- 11 mmHg, respectively (p-values for difference 0.33 and 0.88). Although E. coli bacteriuria was not associated with the blood pressure as a continuous variable, it was associated with the development of hypertension during follow-up (OR 2.8, 95% CI 1.4-5.5).Conclusion: E. coli bacteriuria may increase the risk of future hypertension. (C) 2009 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Viral infections are characterized by a dynamic interplay between the pathogen and defensive innate and adaptive immune responses of the host (35, 38). Upon infection, virus-specific structural components are recognized by pattern recognition receptors of the host, which triggers a mechanism aimed at the suppression of virus replication and eventually virus elimination. Each virus has a characteristic signature of triggering innate immune receptors and methods to counteract immune responses of the host, which ultimately results in an immune response tailored to the particular properties of the infecting virus (6). Most insights into the sequence of events occurring during viral infections have been obtained from animal experiments, where the immunological control of viral infections can be studied in detail. In many murine models, the crucial role of CD8+ T cells in complete elimination of the virus during acute infections has been well established (9, 20, 27). However, both virus-induced damage and immune pathology might contribute to the disease, depending on the type of viral infection and/or the intensity of the innate and adaptive immune responses triggered (10, 20, 37, 41, 49, 60). Primary infections with respiratory syncytial virus (RSV) can cause severe bronchiolitis and pneumonia in infants (24). For RSV, the mouse is not a good model to study primary disease because the virus replicates poorly in murine cells. Hence, to obtain insight into the mechanism of disease caused by RSV, infection studies in humans or nonhuman primate models are needed. We and others have shown that RSV infection causes a strong influx of neutrophils into the airways (15, 25, 48). In addition, we have recently shown that substantial virus-specific CD8+ T-cell responses can be elicited in infants with severe RSV infections (25). However, it is still a controversial issue whether the severe manifestations of lower respiratory tract disease are caused directly by the virus or by innate and/or adaptive immune responses triggered by RSV (8, 20, 31, 57). In our previous work, we found no relation between the severity of disease and the number of virus-specific CD8+ T cells in peripheral blood (25). Moreover, a direct role of the viral load or different viral strains in disease severity has not been established convincingly (11, 59). Data on the development of primary T-cell responses in infants (

Following infection with respiratory syncytial virus (RSV), reinfection in healthy individuals is common and presumably due to ineffective memory T cell responses. In peripheral blood of healthy adults, a higher CD4+/CD8+ memory T cell ratio was observed compared with the ratio of virus-specific effector CD4+/CD8+ T cells that we had found in earlier work during primary RSV infections. In mice, we show that an enhanced ratio of RSV-specific neutralizing to nonneutralizing Abs profoundly enhanced the CD4+ T cell response during RSV infection. Moreover, FcγRs and complement factor C1q contributed to this Ab-mediated enhancement. Therefore, the increase in CD4+ memory T cell response likely occurs through enhanced endosomal Ag processing dependent on FcγRs. The resulting shift in memory T cell response was likely amplified by suppressed T cell proliferation caused by RSV infection of APCs, a route important for Ag presentation via MHC class I molecules leading to CD8+ T cell activation. Decreasing memory CD8+ T cell numbers could explain the inadequate immunity during repeated RSV infections. Understanding this interplay of Ab-mediated CD4+ memory T cell response enhancement and infection mediated CD8+ memory T cell suppression is likely critical for development of effective RSV vaccines.

In the respiratory tract, different dendritic cell (DC) populations guard a tight balance between tolerance and immunity to infectious or harmless materials to which the airways are continuously exposed. For infectious and noninfectious antigens administered via different routes, different subsets of DC might contribute during the induction of T-cell tolerance and immunity. We studied the impact of primary respiratory syncytial virus (RSV) infection on respiratory DC composition in C57BL/6 mice. We also tracked the migration of respiratory DC to the lymph nodes and studied antigen presentation by lung-derived and lymph node-resident DC to CD4 + and CD8 + T cells. We observed a massive influx of mainly CD103 − CD11b high CD11c + conventional DC (cDC) and plasmacytoid DC during the first 7 days of RSV infection, while CD103 + CD11b low CD11c + cDC disappeared from the lung. The two major subsets of lung tissue DC, CD103 + CD11b low CD11c + and CD103 − CD11b high CD11c + cDC, both transported RSV RNA to the lung-draining lymph node. Furthermore, these lung-derived cDC subsets as well as resident LN DC, which did not contain viral RNA, displayed viral antigen by major histocompatibility complex class I and class II to CD8 + and CD4 + T cells. Taken together, our data indicate that during RSV infections, at least three DC subsets might be involved during the activation of lymph node-homing naïve and memory CD4 + and CD8 + T cells.

The Sixth International Conference on Cryptococcus and Cryptococcosis (ICCC) was a well organized meeting held in Boston, Massachusetts in June 2005. The meeting was attended by a record number of 255 participants, presenting 130 oral and poster presentations. After an exciting Genomics workshop – featuring comparative analyses of the sequences along with cutting edge discussions of methods to mine the databases, the meeting began with a comprehensive overview of the most recent hallmarks in cryptococcal research presented by Dr Arturo Casadevall (Albert Einstein College of Medicine, Bronx, NY, USA). Throughout the following 5 days, nearly all aspects of current Crypto-research from the bench to the bedside were covered. Before I begin an overview of the scientific content of the meeting, I start with a disclaimer. It will be impossible to discuss, let alone mention every significant observation reported in the meeting. However, I will try to touch on the main topics that were discussed in the context of both Cryptococcus and Cryptococcosis. Due to space constraints, I will only review the oral presentations, without intending to understate the high quality of the science presented during the two poster sessions (S8 and S11). In the opening address, Dr Casadevall emphasized the uniqueness of the current Cryptococcus neoformans research area. The field has now evolved into a full-grown research area, with genomes from several strains and serotypes fully sequenced and annotated, powerful genetics available, important virulence factors identified and many host interactions unravelled – all reached in a highly coherent and cooperative society. One of the most important virulence factors, the large polysaccharide capsule, has been subject of detailed analyses in the Casadevall lab, yielding several remarkable characteristics. Determination of the molecular mass of capsular glucuronoxylomannan (GXM) from different strains revealed that GXM is the largest polysaccharide isolated from microorganisms, with an …

To determine the contribution of vascular endothelial growth factor (VEGF) to cerebral edema formation in bacterial meningitis, we used a VEGF neutralizing antibody to block VEGF in rabbits, following induction of meningitis by intracisternal inoculation with 109 heat-killed pneumococci. At 8 h, cerebrospinal fluid (CSF) VEGF was significantly elevated in infected untreated animals, and correlated with CSF white blood cell (WBC) count (r=0.56, P=0.004), and brain water content (r=0.42, P=0.04). Blocking of VEGF did not attenuate brain edema, blood–brain barrier disruption, or CSF pleocytosis. The functional role of VEGF in the pathophysiology of BM remains elusive.

Contains fulltext : 58837.pdf (Publisher’s version ) (Closed access) The capsular polysaccharide glucuronoxylomannan (GXM) of Cryptococcus neoformans has been shown to interfere with neutrophil migration. Although several receptors have been implied to mediate this process, the structural perspectives are unknown. Here, we assess the contribution of 6-O-acetylation and xylose substitution of the (1-->3)-alpha-d-mannan backbone of GXM, the variable structural features of GXM, to the interference with neutrophil migration. We compare chemically deacetylated GXM and acetyl- or xylose-deficient GXM from genetically modified strains with wild-type GXM in their ability to inhibit the different phases of neutrophil migration. Additionally, we verify the effects of de-O-acetylation on neutrophil migration in vivo. De-O-acetylation caused a dramatic reduction of the inhibitory capacity of GXM in the in vitro assays for neutrophil chemokinesis, rolling on E-selectin and firm adhesion to endothelium. Genetic removal of xylose only marginally reduced the ability of GXM to reduce firm adhesion. In vivo, chemical deacetylation of GXM significantly reduced its ability to interfere with neutrophil recruitment in a model of myocardial ischemia (65% reduction vs a nonsignificant reduction in tissue myeloperoxidase, respectively). Our findings indicate that 6-O-acetylated mannose of GXM is a crucial motive for the inhibition of neutrophil recruitment.

In bacterial meningitis, neurological damage is associated with a high influx of polymorphonuclear leukocytes (PMN) into the brain. Previous data suggest that the capsular component of the fungus C. neoformans , glucuronoxylomannan (GXM), interferes with PMN-migration into the cerebrospinal fluid (CSF). Therefore, a rabbit model of bacterial meningitis was treated intravenously with GXM. This resulted in (1) a reduction of PMN in the CSF at 6 h ( P =0.05), (2) reduced peak TNF-α concentrations in the CSF, and (3) diminished tissue inflammation and intravascular margination of PMN in GXM-treated animals. Thus, GXM may represent a novel adjuvant anti-inflammatory agent in bacterial meningitis.

Respiratory syncytial virus (RSV) bronchiolitis triggers a strong innate immune response characterized by excessive neutrophil infiltration which contributes to RSV induced pathology. The cytokine IL-17A enhances neutrophil infiltration into virus infected lungs. IL-17A is however best known as an effector of adaptive immune responses. The role of IL-17A in early immune modulation in RSV infection is unknown. We aimed to elucidate whether local IL-17A facilitates the innate neutrophil infiltration into RSV infected lungs prior to adaptive immunity. To this end, we studied IL-17A production in newborns that were hospitalized for severe RSV bronchiolitis. In tracheal aspirates we measured IL-17A concentration and neutrophil counts. We utilized cultured human epithelial cells to test if IL-17A regulates RSV infection-induced IL-8 release as mediator of neutrophil recruitment. In mice we investigated the cell types that are responsible for early innate IL-17A production during RSV infection. Using IL-17A neutralizing antibodies we tested if IL-17A is responsible for innate neutrophil infiltration in mice. Our data show that increased IL-17A production in newborn RSV patient lungs correlates with subsequent neutrophil counts recruited to the lungs. IL-17A potentiates RSV-induced production of the neutrophil-attracting chemokine IL-8 by airway epithelial cells in vitro. Various lung-resident lymphocytes produced IL-17A during early RSV infection in Balb/c mice, of which a local population of CD4 T cells stood out as the predominant RSV-induced cell type. By removing IL-17A during early RSV infection in mice we showed that IL-17A is responsible for enhanced innate neutrophil infiltration in vivo. Using patient material, in vitro studies, and an animal model of RSV infection, we thus show that early local IL-17A production in the airways during RSV bronchiolitis facilitates neutrophil recruitment with pathologic consequences to infant lungs.

Genomic variation and related evolutionary dynamics of human respiratory syncytial virus (RSV), a common causative agent of severe lower respiratory tract infections, may affect its transmission behavior. RSV evolutionary patterns are likely to be influenced by a precarious interplay between selection favoring variants with higher replicative fitness and variants that evade host immune responses. Studying RSV genetic variation can reveal both the genes and the individual codons within these genes that are most crucial for RSV survival. In this study, we conducted genetic diversity and evolutionary rate analyses on 36 RSV subgroup B (RSV-B) whole-genome sequences. The attachment protein, G, was the most variable protein; accordingly, the G gene had a higher substitution rate than other RSV-B genes. Overall, less genetic variability was found among the available RSV-B genome sequences than among RSV-A genome sequences in a comparable sample. The mean substitution rates of the two subgroups were, however, similar (for subgroup A, 6.47 × 10 −4 substitutions/site/year [95% credible interval {CI 95%}, 5.56 × 10 −4 to 7.38 × 10 −4 ]; for subgroup B, 7.76 × 10 −4 substitutions/site/year [CI 95%, 6.89 × 10 −4 to 8.58 × 10 −4 ]), with the time to their most recent common ancestors (TMRCAs) being much lower for RSV-B (19 years) than for RSV-A (46.8 years). The more recent RSV-B TMRCA is apparently the result of a genetic bottleneck that, over longer time scales, is still compatible with neutral population dynamics. Whereas the immunogenic G protein seems to require high substitution rates to ensure immune evasion, strong purifying selection in conserved proteins such as the fusion protein and nucleocapsid protein is likely essential to preserve RSV viability.

Novel viruses might be responsible for numerous disease cases with unknown etiology. In this study, we screened 1800 nasopharyngeal samples from adult outpatients with respiratory disease symptoms and healthy individuals. We employed a reverse transcription (RT)-PCR assay and CODEHOP-based primers (CT12-mCODEHOP) previously developed to recognize known and unknown corona- and toroviruses. The CT12-mCODEHOP assay detected 42.0 % (29/69) of samples positive for human coronaviruses (HCoV), including HCoV-229 (1/16), HCoV-NL63 (9/17), and HCoV-OC43 (19/36), and additionally HCoV-HKU1 (3), which was not targeted by the diagnostic real-time PCR assays. No other coronaviruses were identified in the analyzed samples.

Objective Opioids are frequently used during mechanical ventilation for severe viral infection in infancy. Opioid receptors have immunomodulatory properties, but nothing is known about their antiviral effects. We therefore aimed to investigate the role of opioid receptors in virus-induced airway inflammation. Patients and interventions Two single nucleotide polymorphisms in OPRM1 and OPRD1 were genotyped in 465 infants with severe respiratory syncytial virus infection and 930 control subjects. Subsequently, the mechanism by which opioid receptors affect clinical outcome in respiratory syncytial virus bronchiolitis was studied in BALB/c mice. Animals were injected daily with nalmefene, a nonselective opioid receptor antagonist, and infected by intranasal inoculation of respiratory syncytial virus 24 hrs after the first dose of nalmefene. The potential therapeutic effect of pharmaceutical opioids was studied using µ (DAMGO), κ (U50488), and Δ (DPDPE) opioid receptor agonists 48 hrs after infection. Measurements and main results In our human study, the A118G single nucleotide polymorphism rs1799971 was associated with respiratory syncytial virus disease severity (p = 0.015). In mice, nalmefene treatment increased viral titers and was associated with more pronounced weight loss. Increased viral replication was associated with increased levels of cytokines and chemokines in the bronchoalveolar lavage fluid, enhanced bronchoalveolar cellular influx, and exaggerated lung pathology. Pharmaceutical opioids, in particular DPDPE, did not affect viral replication. They did induce a decreased influx of neutrophils, but an increased influx of lymphocytes and monocytes into the bronchoalveolar lumen during respiratory syncytial virus infection. Conclusions Using a human study and an experimental model, we show that opioid receptor signaling has a potential beneficial role in the outcome of respiratory viral disease. We show that opioid receptor signaling is required to control respiratory syncytial virus replication and thereby to control disease severity. However, we also show that caution is required before using pharmaceutical opioids as anti-inflammatory or antiviral treatment of patients with viral respiratory infection.

Immunological checkpoints, such as the inhibitory CD200 receptor (CD200R), play a dual role in balancing the immune system during microbial infection. On the one hand these inhibitory signals prevent excessive immune mediated pathology but on the other hand they may impair clearance of the pathogen. We studied the influence of the inhibitory CD200-CD200R axis on clearance and pathology in two different virus infection models. We find that lack of CD200R signaling strongly enhances type I interferon (IFN) production and viral clearance and improves the outcome of mouse hepatitis corona virus (MHV) infection, particularly in female mice. MHV clearance is known to be dependent on Toll like receptor 7 (TLR7)-mediated type I IFN production and sex differences in TLR7 responses previously have been reported for humans. We therefore hypothesize that CD200R ligation suppresses TLR7 responses and that release of this inhibition enlarges sex differences in TLR7 signaling. This hypothesis is supported by our findings that in vivo administration of synthetic TLR7 ligand leads to enhanced type I IFN production, particularly in female Cd200−/− mice and that CD200R ligation inhibits TLR7 signaling in vitro. In influenza A virus infection we show that viral clearance is determined by sex but not by CD200R signaling. However, absence of CD200R in influenza A virus infection results in enhanced lung neutrophil influx and pathology in females. Thus, CD200-CD200R and sex are host factors that together determine the outcome of viral infection. Our data predict a sex bias in both beneficial and pathological immune responses to virus infection upon therapeutic targeting of CD200-CD200R., Author Summary Immune responses need to be carefully orchestrated to prevent disease due to an overactive immune system. Immunological checkpoints are provided by immune inhibitory receptors, which set a threshold for activation and dampen the immune system. In the case of a viral infection, this prevents pathology induced by the immune system, but on the other hand may prevent adequate removal of the virus. In this paper, we show that removal of such an immunological checkpoint in mice leads to rapid removal of corona virus, but also to more immune-induced disease symptoms in case of influenza virus infection. We observe this predominantly in female mice. We demonstrate that this particular checkpoint inhibits anti-viral responses that are naturally stronger in females. Release of this checkpoint enlarges these sex differences. Our findings have major implications for therapeutic use of blockers of this pathway, which are currently in clinical trials for the treatment of cancer, as we predict that female patients will have a stronger response to such therapeutics.

Human respiratory syncytial virus (RSV) is an important cause of severe lower respiratory tract infections in infants and the elderly. In the vast majority of cases, however, RSV infections run mild and symptoms resemble those of a common cold. The immunological, clinical, and epidemiological profile of severe RSV infections suggests a disease caused by a virus with typical seasonal transmission behavior, lacking clear-cut virulence factors, but instead causing disease by modifying the host's immune response in a way that stimulates pathogenesis. Yet, the interplay between RSV-evoked immune responses and epidemic behavior, and how this affects the genomic evolutionary dynamics of the virus, remains poorly understood. Here, we present a comprehensive collection of 33 novel RSV subgroup A genomes from strains sampled over the last decade, and provide the first measurement of RSV-A genomic diversity through time in a phylodynamic framework. In addition, we map amino acid substitutions per protein to determine mutational hotspots in specific domains. Using Bayesian genealogical inference, we estimated the genomic evolutionary rate to be 6.47×10(-4) (credible interval: 5.56×10(-4), 7.38×10(-4)) substitutions/site/year, considerably slower than previous estimates based on G gene sequences only. The G gene is however marked by elevated substitution rates compared to other RSV genes, which can be attributed to relaxed selective constraints. In line with this, site-specific selection analyses identify the G gene as the major target of diversifying selection. Importantly, statistical analysis demonstrates that the immune driven positive selection does not leave a measurable imprint on the genome phylogeny, implying that RSV lineage replacement mainly follows nonselective epidemiological processes. The roughly 50 years of RSV-A genomic evolution are characterized by a constant population size through time and general co-circulation of lineages over many epidemic seasons - a conclusion that might be taken into account when developing future therapeutic and preventive strategies. ispartof: PLoS One vol:7 issue:12 ispartof: location:United States status: published

The bipartite POU domain of transcription factor Oct-1 stimulates adenovirus DNA replication through an interaction with the octamer sequence present in the auxiliary origin. Employing an immobilized in vitro DNA replication system, we show that the POU domain enhances the formation of a pre-initiation complex composed of the viral precursor terminal protein-DNA polymerase (pTP-pol) complex and the origin. To investigate the mechanism of stimulation we have explored protein-protein interactions between the POU domain and the pTP-pol complex. Such an interaction could be detected using a GST-POU fusion protein bound to glutathione-agarose beads. Binding was also observed with the POU homeodomain (POUHD), albeit weaker than with the intact POU domain, but not with the POU specific subdomain. Four point mutations localized in the POUHD were analyzed for pTP-pol binding. Two of these, E22A and E30A, bound pTP-pol equally as well as the wild-type, while the other two, Q24A and E29A, were able to bind 2- to 4-fold better. These mutations are localized in the same region where the HSV transactivator VP16 binds, but did not coincide with the VP16 contacts. A direct correlation between pTP-pol binding and stimulation of DNA replication in vitro was observed for all mutants, suggesting that stimulation by the POU domain is caused by an interaction with the viral pTP-pol complex.

The DNA-binding domain of Nuclear Factor I (NFIBD) enhances initiation of adenovirus DNA replication up to 50-fold by binding to the auxiliary region of the origin and positioning the viral DNA polymerase. To study if and when NFIBD dissociates from the template, we immobilized origin DNA to glutathione-agarose beads by means of a GST-NFIBD fusion protein. This immobilized template is active in replication. By analyzing the release of prelabeled templates from the beads under different conditions, we show that NFIBD dissociates already early during initiation. During preinitiation NFIBD remains bound, but as soon as dCTP, dATP or dTTP are added, efficient dissociation occurs. A much lower dissociation level was induced by addition of dGTP. Since dCTP, dATP and dTTP are required for formation of a pTP-CAT initiation intermediate, we explain our results by conformational changes occurring in the polymerase during initiation leading to disruption of both the interaction between the polymerase and NFI as well as the interaction between NFI and the DNA.

Inactivated respiratory syncytial virus (RSV) vaccines tend to predispose for immune mediated enhanced disease, characterized by Th2 responses and airway hypersensitivity reactions. We show in a C57BL/6 mouse model that the early innate response elicited by the challenge virus (RSV versus influenza virus) influences the outcome of the Th1/Th2 balance in the lung after intramuscular priming with inactivated vaccine. Priming of CD4(+)/IFN-gamma(+) T cells by mature dendritic cells administered intravenously and/or priming of a virus specific CD8(+) T cell response ameliorated the Th2-mediated inflammatory response in the lung, suggesting that vaccination procedures are feasible that prevent vaccine induced immune pathology. (C) 2011 Elsevier Ltd. All rights reserved.

In 540% of respiratory infections in children, the diagnostics remain negative, suggesting that the patients might be infected with a yet unknown pathogen. Virus discovery cDNA-AFLP (VIDISCA) is a virus discovery method based on recognition of restriction enzyme cleavage sites, ligation of adaptors and subsequent amplification by PCR. However, direct discovery of unknown pathogens in nasopharyngeal swabs is difficult due to the high concentration of ribosomal RNA (rRNA) that acts as competitor. In the current study we optimized VIDISCA by adjusting the reverse transcription enzymes and decreasing rRNA amplification in the reverse transcription, using hexamer oligonucleotides that do not anneal to rRNA. Residual cDNA synthesis on rRNA templates was further reduced with oligonucleotides that anneal to rRNA but can not be extended due to 3′-dideoxy-C6-modification. With these modifications >90% reduction of rRNA amplification was established. Further improvement of the VIDISCA sensitivity was obtained by high throughput sequencing (VIDISCA-454). Eighteen nasopharyngeal swabs were analysed, all containing known respiratory viruses. We could identify the proper virus in the majority of samples tested (11/18). The median load in the VIDISCA-454 positive samples was 7.2 E5 viral genome copies/ml (ranging from 1.4 E37.7 E6). Our results show that optimization of VIDISCA and subsequent high-throughput-sequencing enhances sensitivity drastically and provides the opportunity to perform virus discovery directly in patient material.

Toll-like receptors (TLRs) play a distinct role in battling respiratory syncytial virus (RSV) infections. However, due to a lack of representative animal models and several early controversies, the field is unclear. In this systematic review, we have elucidated conflicting results and outlined important factors that might affect study outcomes. We reviewed studies that used different doses/viral strains, performed virus propagation in different cell lines, or used different mice strains. The following firm conclusions can be drawn: multiple TLRs activate innate immunity upon RSV infection; TLR4 can influence TLR2 expression, suggesting that optimal induction of multiple signaling pathways is required to elicit protective, rather than deleterious innate immune responses following infection; in mice, TLR4, TLR2/-6, and TLR7 have immune-stimulating properties, while TLR3 activation occurs later and appears to downregulate immune responses; in humans, polymorphism studies have demonstrated an important role for TLR4-signaling; and activation of TLR-signaling leads to antiviral cytokine production, such as TNF-a and IFNs. Viral factors may block these pathways, thereby contributing to immune evasion and RSV survival. A better understanding of the complex interplay between TLRs and severe RSV infections might lead to efficient prophylactic and therapeutic treatments, as well as the development of adequate vaccines combined with TLR adjuvants.

Influenza virus infection can be accompanied by life-threatening immune pathology most likely due to excessive antiviral responses. Inhibitory immune receptors may restrain such overactive immune responses. To study the role of the inhibitory immune receptor CD200R and its ligand CD200 during influenza infection, we challenged wild-type and CD200−/− mice with influenza virus. We found that CD200−/− mice in comparison to wild-type controls when inoculated with influenza virus developed more severe disease, associated with increased lung infiltration and lung endothelium damage. CD200−/− mice did develop adequate adaptive immune responses and were able to control viral load, suggesting that the severe disease was caused by a lack of control of the immune response. Interestingly, development of disease was completely prevented by depletion of T cells before infection, despite dramatically increased viral load, indicating that T cells are essential for the development of disease symptoms. Our data show that lack of CD200-CD200R signaling increases immune pathology during influenza infection, which can be reduced by T cell depletion.

The origin of DNA replication of many human adenoviruses is composed of a highly conserved core origin and an auxiliary region, containing the binding sites for NFI and NFIII/Oct-1. We examined enhancement of DNA replication in vitro by the purified functional DNA-binding domains of NFI (NFI-BD) and NFIII/Oct-1 (the POU domain), using origins in which the positions of the binding sites for these proteins were transposed. Insertion or deletion of two or three base pairs between the core origin and the NFI binding site resulted in a 3-5-fold decrease of stimulation, whereas larger insertions gradually reduced the stimulation further. Mutants in which the NFI binding site was separated approximately one or two helical turns from the core origin by AT-rich sequences could still be stimulated by NFI. In contrast, insertion of two or more base pairs between the NFI and NFIII/Oct-1 binding sites abolished stimulation by NFIII/Oct-1 almost completely. Furthermore, stimulation by this protein was lost when the Ad2 NFIII/Oct-1 binding site was transposed to a position closer to the core origin, destroying the NFI binding site. This shows that the position of the NFIII/Oct-1 binding site is essential for stimulation. Models to explain these position-dependent effects on stimulation are discussed.

We have isolated a cDNA encoding the 84-kD subunit of NFIV. Tryptic peptide sequences were identified within the coding sequences, confirming its proper identity. The primary sequence of the protein is identical to that of the large subunit of the Ku autoantigen. A missing NFIV peptide sequence was identified within the sequence of the small subunit of Ku. In addition, the proteins are identical in immunological aspects. We suggest that the Ku and NFIV proteins are identical. This connection adds new biochemical data to our knowledge of the Ku autoantigen.

Cryptococcus neoformans is the causative agent of cryptococcal meningoencephalitis. There is accumulating evidence that C. neoformans is a facultative intracellular pathogen, residing in macrophages and endothelium. The molecular mechanism conferring resistance to phagolysosomal killing in these cells is a key unresolved issue. To gain insight into the fungal adaptive strategies, serial analysis of gene expression was used to map genes differentially expressed in an intraphagocytic environment. By comparing transcript profiles of C. neoformans serotype D B3501 cells recovered from endothelial cells with those from free-grown cryptococci, we identified the cryptococcal homologue of the SKN7 two-component stress response regulator gene from Saccharomyces cerevisiae. Studies with C. neoformans cells disrupted for SKN7 revealed an increased susceptibility to t-butyl hydroperoxide (100% lethality at 0.7 mM, vs. 1.0 mM for wild type) and significantly lower survival rates in endothelial infection experiments. Mice experiments revealed that SKN7 disruption strongly attenuates cryptococcal virulence in vivo. We propose that Skn7 (co-)regulates the fungal adaptive strategy, allowing intraphagocytic survival by conferring resistance to phagolysosomal killing in endothelial cells.

Background The capsular polysaccharide glucuronoxylomannan (GXM) of Cryptococcus neoformans interferes with the chemotaxis and transendothelial migration of neutrophils. Intravenous administration of purified GXM has been shown to reduce the influx of inflammatory cells in an animal model of bacterial infection. Here we show that isolated GXM can also interfere with neutrophil migration in a model of inflammation not related to infection. We assessed the effects of intravenous GXM on neutrophil infiltration in a rat model of myocardial ischaemia, where neutrophil infiltration has been shown to contribute to postischaemic reperfusion injury. Materials and methods Rats were subjected to coronary artery ligation followed by a 3-h reperfusion period. Myeloperoxidase-activity was measured in the ischaemic tissues as a marker of neutrophil infiltration. Results Intravenous administration of GXM markedly reduced the influx of neutrophils in the ischaemic myocardium as measured by a 65% reduction of tissue MPO activity. This reduction of MPO activity was clearly correlated to the serum concentration of GXM. As complement activation by GXM was minimal at the doses applied in vivo, it is unlikely that generation of chemotactic C5a in the circulation by GXM caused the observed reduction in leucocyte migration. Conclusion Purified cryptococcal GXM has the ability to reduce neutrophil influx even outside the scope of infection.

The major capsular polysaccharide glucuronoxylomannan (GXM) of the pathogenic fungus Cryptococcus neoformans has been associated with depression of a variety of immunological host responses. For one, GXM has been shown to interfere with the migration of phagocytes to sites of inflammation by interference with both chemokinesis and leucocyte adhesion to the endothelium. We reported previously that GXM blocks the firm adhesion of neutrophils (PMNs) to endothelium in a static adhesion model, most probably by interfering with E-selectin binding pathways. Using a flow model, we now demonstrate that GXM also interferes with the initial rolling phase of PMN adhesion to endothelium (40% decrease) as well as to E-selectin-transfected CHO cells (43% inhibition). Furthermore, we show that CD14 and TLR4, which are known receptors for GXM, mediate this interference with PMN rolling. However, thus far, we are not able to identify the ligand of E-selectin on the surface of PMNs that is specifically affected by GXM. In conclusion, cryptococcal GXM interferes with both rolling and fixed binding of neutrophils on the endothelium, providing a novel means of contributing to the absence of neutrophil infiltration observed in cryptococcal infections.

An important virulence factor of the pathogenic fungus Cryptococcus neoformans is its polysaccharide capsule. The capsular polysaccharides glucuronoxylomannan (GXM), galactoxylomannan (GalXM) and the mannoproteins (MPs) display various immunomodulatory effects on the host response, such as the inhibition of phagocytosis, suppression of T-cell mediated immunity, and induction of immunogenic tolerance. Moreover, these capsular polysaccharides are able to interfere with the migration of phagocytes despite adequate stimulation of chemokine production and their concerted action accounts for the mild inflammatory response often observed in cryptococcosis. Different mechanisms contribute to this phenomenon. First, cryptococcal polysaccharides impair leukocyte migration towards chemoattractants. A combination of the intrinsic chemoattracting properties of circulating polysaccharides and the ability to induce cross-desensitization of chemokine receptors prevents leukocytes from leaving the bloodstream and migrating towards inflammatory site. Polysaccharide-induced repressive effects on the C5a receptor expression on neutrophils may also add to this impaired chemokinesis. Second, polysaccharides interfere with leukocyte adhesion to and migration through the endothelium. Both GXM and MP-4 induce L-selectin shedding from the surface of leukocytes; hence, interference with leukocyte rolling on the endothelium can be expected. GXM also interferes with the subsequent process of firm leukocyte adhesion to the endothelium in vitro. Thirdly, capsular polysaccharides enhance the production of anti-inflammatory interleukin-10 (IL-10) and induce tumor necrosis factor-alpha (TNFalpha) receptor loss from the surface of neutrophils. The capacity to reduce neutrophil influx makes cryptococcal polysaccharides interesting compounds to study in clinical models of inflammation (i.e.; sepsis, auto-immune disorders) in which leukocyte influx can be potentially damaging to host tissues.

PURPOSE: With the increasing problem of resistance in pathogenic microorganisms the development of nonantimicrobial therapies is important. Diabetes mellitus (DM) is associated with an increased incidence of urinary tract infections. The majority of Escherichia coli strains, which is the most prevalent uropathogen, have type 1 fimbriae that bind to uroplakin in the bladder, as mediated by the adhesin FimH. A vaccine is being developed based on FimH adhesion. MATERIALS AND METHODS: The sequence of FimH adhesion of 29 E. coli strains isolated from women with DM was determined. For adherence experiments we used E. coli isolated from women with DM and a T24 bladder cell line as well as the 2 well-defined type 1 fimbriated E. coli strains Ctrl 39 and NU14, and uroepithelial cells from women with DM. RESULTS: The fimH sequence of E. coli strains isolated from women with DM was highly homologous to the known fimH sequence of E. coli from patients without DM. Adherence assays in a T24 bladder cell line showed that adherence of these E. coli strains from women with DM could be inhibited by pre-incubation with antiserum raised against the chaperone-adhesin complex FimC-FimH. AntiFimCH antiserum also inhibited the adherence of the 2 well-defined E. coli strains expressing type 1 fimbriae, NU14 and Ctrl 39, but not of the FimH mutant strain NU14 H-, to uroepithelial cells from women with DM. CONCLUSIONS: These findings suggest that a vaccine based on FimH adhesin of type 1 fimbriated E. coli is a potential method of preventing urinary tract infection in women with DM

Contains fulltext : 57852.pdf (Publisher’s version ) (Closed access) BACKGROUND: Patients with cryptococcal meningitis (CM) show elevated intracranial pressure (ICP) and blood-brain barrier (BBB) disruption in most cases. Elevated ICP is an important contributor to mortality. Vascular endothelial growth factor (VEGF) might be the mediator of BBB disruption during CM. METHODS: We measured VEGF levels in serum, plasma, and cerebrospinal fluid (CSF) of 95 patients and 63 control subjects, and we analyzed the required trigger and cellular source of VEGF secretion in vitro. RESULTS: Cryptococcus neoformans and its capsular antigens dose-dependently induced VEGF secretion by polymorphonuclear neutrophils, monocytes, and peripheral blood mononuclear cells (PBMCs). VEGF production by PBMCs induced by antigens strongly exceeded production by monocytes (P